Wow, I'm coming into this thread late ...

To answer Godmar up-thread, Evergreen's OpenSearch service returns
data in more than 15 formats, including MARCXML and MODS.  It was
actually the first ILS to do so (with the exception of Ross's Voyager
add-on), and also the first ILS to have an unAPI service (which it
embeds <link> elements to expose -- part of the non-validation you
pointed out).  Non-validation (by extension) is an acceptible
trade-off in my opinion, since feed readers (the main consumers of
ATOM and RSS today -- think a Saved Searches folder in Google Reader
or Live Bookmarks your bookmark toolbar) have no problem with the
data.

Some examples:

HTML, with links:
http://dev.gapines.org/opac/extras/opensearch/1.1/-/html-full?searchOrg=PINES&searchTerms=harry+potter&searchClass=keyword

MARCXML: http://dev.gapines.org/opac/extras/opensearch/1.1/-/marcxml?searchOrg=PINES&searchTerms=harry+potter&searchClass=keyword

MARCXML with some extensions (view source):
http://dev.gapines.org/opac/extras/opensearch/1.1/-/marcxml-full?searchOrg=PINES&searchTerms=harry+potter&searchClass=keyword

MODS: http://dev.gapines.org/opac/extras/opensearch/1.1/-/mods3?searchOrg=PINES&searchTerms=harry+potter&searchClass=keyword

OAI DC: http://dev.gapines.org/opac/extras/opensearch/1.1/-/oai_dc?searchOrg=PINES&searchTerms=harry+potter&searchClass=keyword

RSS 2.0: http://dev.gapines.org/opac/extras/opensearch/1.1/-/rss2?searchOrg=PINES&searchTerms=harry+potter&searchClass=keyword

and even a catalog card mock-up:
http://dev.gapines.org/opac/extras/opensearch/1.1/-/htmlholdings?searchOrg=PINES&searchTerms=harry+potter&searchClass=keyword


On Tue, Jun 24, 2008 at 3:36 PM, Ross Singer <[log in to unmask]> wrote:
[snip]
> What accept header would you use for marcxml, mods or dc?
>

According to the W3C, application/marc-xml or similar (the '-' instead
of '+' says it's not a registered MIME type).  However, browsers don't
work with that well.  Put a '+' in there and they'll (generally)
render the XML.

-- 
Mike Rylander
 | VP, Research and Design
 | Equinox Software, Inc. / The Evergreen Experts
 | phone: 1-877-OPEN-ILS (673-6457)
 | email: [log in to unmask]
 | web: http://www.esilibrary.com